Single action tissue sealer

ABSTRACT

An endoscopic bipolar forceps includes a housing and a shaft, the shaft having an end effector assembly at its distal end. The end effector assembly includes two jaw members for grasping tissue therebetween. The jaw members are adapted to connect to an electrosurgical energy source which enable them to conduct energy through the tissue to create a tissue seal. A drive assembly is disposed within the housing which moves the jaw members. A switch is disposed within the housing which activates the electrosurgical energy. A knife assembly is included which is advanceable to cut tissue held between the jaw members. A movable handle is connected to the housing. Continual actuation of the movable handle engages the drive assembly to move the jaw members, engages the switch to activate the electrosurgical energy source to seal the tissue, and advances the knife assembly the cut the tissue disposed between the jaw members.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/633,554 filed Oct. 2, 2012, now abandoned, which is acontinuation of U.S. application Ser. No. 12/621,056 filed Nov. 18,2009, now U.S. Pat. No. 8,277,447, which is a continuation of U.S.application Ser. No. 11/207,956 filed Aug. 19, 2005, now U.S. Pat. No.7,628,791, the entire contents of each of which are incorporated hereinby reference.

BACKGROUND

The present disclosure relates to an electrosurgical forceps and moreparticularly, the present disclosure relates to an endoscopic bipolarelectrosurgical forceps for manipulating, clamping, sealing and cuttingtissue in a single action.

TECHNICAL FIELD

Electrosurgical forceps utilize both mechanical clamping action andelectrical energy to affect hemostasis by heating the tissue and bloodvessels to coagulate, cauterize and/or seal tissue. As an alternative toopen forceps for use with open surgical procedures, many modern surgeonsuse endoscopes and endoscopic instruments for remotely accessing organsthrough smaller, puncture-like incisions. As a direct result thereof,patients tend to benefit from less scarring and reduced healing time.

Endoscopic instruments are inserted into the patient through a cannula,or port, which has been made with a trocar. Typical sizes for cannulasrange from about three millimeters to about 12 millimeters. Smallercannulas are usually preferred, which, as can be appreciated, ultimatelypresents a design challenge to instrument manufacturers who look forways to make endoscopic instruments that fit through the smallercannulas.

Many endoscopic surgical procedures require cutting or ligating bloodvessels or vascular tissue. Due to the inherent spatial considerationsof the surgical cavity, surgeons often have difficulty suturing vesselsor performing other traditional methods of controlling bleeding, e.g.,clamping and/or tying-off transected blood vessels. By utilizing anendoscopic electrosurgical forceps, a surgeon can either cauterize,coagulate/desiccate and/or simply reduce or slow bleeding simply bycontrolling the intensity, frequency and duration of the electrosurgicalenergy applied through the jaw members to the tissue. Most small bloodvessels, i.e., in the range below two millimeters in diameter, can oftenbe closed using standard electrosurgical instruments and techniques.However, if a larger vessel is ligated, it may be necessary for thesurgeon to convert the endoscopic procedure into an open-surgicalprocedure and thereby abandon the benefits of endoscopic surgery.Alternatively, the surgeon can seal the larger vessel or tissue.

It is thought that the process of coagulating vessels is fundamentallydifferent from electrosurgical vessel sealing. For the purposes herein,“coagulation” is defined as a process of desiccating tissue wherein thetissue cells are ruptured and dried. “Vessel sealing” or “tissuesealing” is defined as the process of liquefying the collagen in thetissue so that it reforms into a fused mass. Coagulation of smallvessels is sufficient to permanently close them, while larger vesselsneed to be sealed to assure permanent closure.

In order to effectively seal larger vessels (or tissue) two predominantmechanical parameters should be accurately controlled—the pressureapplied to the vessel (tissue) and the gap distance between theelectrodes—both of which are affected by the thickness of the sealedvessel. More particularly, accurate application of pressure is importantto oppose the walls of the vessel; to reduce the tissue impedance to alow enough value that allows enough electrosurgical energy through thetissue; to overcome the forces of expansion during tissue heating; andto contribute to the end tissue thickness which is an indication of agood seal. It has been determined that a typical fused vessel wall isoptimum between about 0.001 and about 0.006 inches. Below this range,the seal may shred or tear and above this range the lumens may not beproperly or effectively sealed.

With respect to smaller vessels, the pressure applied to the tissuetends to become less relevant whereas the gap distance between theelectrically conductive surfaces becomes more significant for effectivesealing. In other words, the chances of the two electrically conductivesurfaces touching during activation increases as vessels become smaller.

As mentioned above, in order to properly and effectively seal largervessels or tissue, a greater closure force between opposing jaw membersis required. It is known that a large closure force between the jawstypically requires a large moment about the pivot for each jaw. Thispresents a design challenge because the jaw members are typicallyaffixed with pins which are positioned to have small moment arms withrespect to the pivot of each jaw member. A large force, coupled with asmall moment arm, is undesirable because the large forces may shear thepins. As a result, designers compensate for these large closure forcesby either designing instruments with metal pins and/or by designinginstruments which at least partially offload these closure forces toreduce the chances of mechanical failure. As can be appreciated, ifmetal pivot pins are employed, the metal pins should be insulated toavoid the pin acting as an alternate current path between the jawmembers which may prove detrimental to effective sealing.

Increasing the closure forces between electrodes may have otherundesirable effects, e.g., it may cause the opposing electrodes to comeinto close contact with one another which may result in a short circuitand a small closure force may cause pre-mature movement of the tissueduring compression and prior to activation. As a result thereof,providing an instrument which consistently provides the appropriateclosure force between opposing electrodes within a preferred pressurerange will enhance the chances of a successful seal. As can beappreciated, relying on a surgeon to manually provide the appropriateclosure force within the appropriate range on a consistent basis wouldbe difficult and the resultant effectiveness and quality of the seal mayvary. Moreover, the overall success of creating an effective tissue sealis greatly reliant upon the user's expertise, vision, dexterity, andexperience in judging the appropriate closure force to uniformly,consistently and effectively seal the vessel. In other words, thesuccess of the seal would greatly depend upon the ultimate skill of thesurgeon rather than the efficiency of the instrument.

It has been found that the pressure range for assuring a consistent andeffective seal is between about 3 kg/cm² to about 16 kg/cm² and,desirably, within a working range of about 7 kg/cm² to about 13 kg/cm².Manufacturing an instrument which is capable of providing a closurepressure within this working range has been shown to be effective forsealing arteries, tissues and other vascular bundles.

Various force-actuating assemblies have been developed in the past forproviding the appropriate closure forces to affect vessel sealing. Forexample, one such actuating assembly has been developed by Valleylab,Inc., of Boulder Colorado, a division of Tyco Healthcare LP, for usewith Valleylab's vessel sealing and dividing instrument commonly soldunder the trademark LIGASURE ATLAS®. This assembly includes a four-barmechanical linkage, a spring and a drive assembly which cooperate toconsistently provide and maintain tissue pressures within the aboveworking ranges. The LIGASURE ATLAS® is presently designed to fit througha 10 mm cannula and includes a bi-lateral jaw closure mechanism which isactivated by a foot switch. A trigger assembly extends a knife distallyto separate the tissue along the tissue seal. A rotating mechanism isassociated with distal end of the handle to allow a surgeon toselectively rotate the jaw members to facilitate grasping tissue.Co-pending U.S. application Ser. Nos. 10/179,863 and 10/116,944 and PCTApplication Serial Nos. PCT/US01/01890 and PCT/7201/11340 describe indetail the operating features of the LIGASURE ATLAS® and various methodsrelating thereto. The contents of all of these applications are herebyincorporated by reference herein.

It would be desirous to develop an instrument that reduces the number ofsteps it takes to perform the tissue seal and cut. Preferably, theinstrument would be able to manipulate, clamp, seal and cut tissue in asingle action (e.g., by squeezing a handle).

SUMMARY

The present disclosure relates to an endoscopic bipolar forceps whichincludes a housing and a shaft affixed to the distal end of the housing.Preferably, the shaft includes a diameter such that the shaft is freelyinsertable through a trocar. The shaft also includes a longitudinal axisdefined therethrough and a pair of first and second jaw members attachedto a distal end thereof The forceps includes a drive assembly for movingthe first jaw member relative to the second member from a first positionwherein the jaw members are disposed in spaced relation relative to eachother to a second position wherein the jaw members cooperate to grasptissue therebetween. A movable handle is included which is rotatableabout a pivot located above the longitudinal axis of the shaft. Movementof the movable handle mechanically cooperates with internal componentsto move the jaw members from the open and closed positions, to clamptissue, to seal tissue and to cut tissue. Advantageously, the pivot islocated a fixed distance above the longitudinal axis to providelever-like mechanical advantage to a drive flange of the drive assembly.The drive flange is located generally along the longitudinal axis. Theforceps is connected to a source of electrosurgical energy which carrieselectrical potentials to each respective jaw member such that the jawmembers are capable of conducting bipolar energy through tissue heldtherebetween to affect a tissue seal.

The forceps includes a switch disposed within the housing which iselectromechanically connected to the energy source. Advantageously, theswitch allows a user to supply bipolar energy to the jaw members toaffect a tissue seal. The switch is activated by contact from a cutterlever or the movable handle itself when a user continues to compress themovable handle after the tissue has been clamped.

The forceps includes an advanceable knife assembly for cutting tissue ina forward direction along the tissue seal. The knife assembly isadvanced when a user continues to compress the movable handle after thetissue has been sealed, forcing the cutter lever forward. A rotatingassembly may also be included for rotating the jaw members about thelongitudinal axis defined through the shaft.

In one embodiment, the movable jaw member includes a first electricalpotential and the fixed jaw member includes a second electricalpotential. A lead connects the movable jaw member to the first potentialand a conductive tube (which is disposed through the shaft) conducts asecond electrical potential to the fixed jaw member. Advantageously, theconductive tube is connected to the rotating assembly to permitselective rotation of the jaw members.

In one embodiment, the drive assembly includes a reciprocating sleevewhich upon activation of the movable handle, translates atop therotating conductive tube to move the movable jaw member relative to thefixed jaw member. In one embodiment, the movable jaw member includes adetent which extends beyond the fixed jaw member which is designed forengagement with the reciprocating sleeve such that, upon translationthereof, the movable jaw member moves relative to the fixed jaw member.Advantageously, a spring is included with the drive assembly tofacilitate actuation of the movable handle and to ensure the closureforce is maintained within the working range of about 3 kg/cm² to about16 kg/cm² and, preferably, about 7 kg/cm² to about 13 kg/cm²

In one embodiment, at least one of the jaw members includes a series ofstop members disposed thereon for regulating the distance between thejaw members (i.e., creating a gap between the two opposing jaw members)during the sealing process. As can be appreciated, regulating the gapdistance between opposing jaw members along with maintaining the closingpressure to within the above-described ranges will produce a reliableand consistent tissue seal.

The present disclosure also relates to an endoscopic bipolar forcepswhich includes a shaft having a movable jaw member and a fixed jawmember at a distal end thereof The forceps also includes a driveassembly for moving the movable jaw member relative to the fixed jawmember from a first position wherein the movable jaw member is disposedin spaced relation relative to the fixed jaw member to a second positionwherein the movable jaw member is closer to the fixed jaw member formanipulating tissue. A movable handle is included which actuates thedrive assembly to move the movable jaw member.

The forceps connects to a source of electrosurgical energy which isconducted to each jaw member such that the jaw members are capable ofconducting bipolar energy through tissue held therebetween to affect atissue seal. Advantageously, the forceps also includes a selectivelyadvanceable knife assembly for cutting tissue in a distal directionalong the tissue seal and a stop member disposed on at least one of thejaw members for regulating the distance between jaw members duringsealing.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the subject instrument are described herein withreference to the drawings wherein:

FIG. 1 is a partial schematic view of one embodiment of an endoscopicbipolar forceps having a movable thumb handle in an unactuated positionaccording to one aspect of the present disclosure;

FIG. 2 is a partial schematic view of the forceps of FIG. 1 illustratedin a partially actuated position;

FIG. 3 is a partial schematic view of another embodiment of anendoscopic bipolar forceps having a movable finger handle illustrated ina partially actuated position;

FIG. 4 is an enlarged, perspective view of an end effector assembly withjaw members shown in an open configuration;

FIG. 5 is an enlarged, side view of the end effector assembly of FIG. 4;

FIG. 6 is an enlarged, perspective view of the tissue contacting side ofan upper jaw member of the end effector assembly;

FIG. 7 is an enlarged, broken perspective view showing the end effectorassembly and highlighting a cam-like closing mechanism which cooperateswith a reciprocating pull sleeve to move the jaw members relative to oneanother;

FIG. 8 is a full perspective view of the end effector assembly of FIG.7;

FIG. 9 is a left, perspective view of a rotating assembly, driveassembly, knife assembly and lower jaw member according to the presentdisclosure;

FIG. 10 is a rear, perspective view of the rotating assembly, driveassembly and knife assembly;

FIG. 11 is an enlarged, top, perspective view of the end effectorassembly with parts separated;

FIG. 12 is an enlarged, perspective view of the knife assembly;

FIG. 13 is an enlarged, perspective view of the rotating assembly;

FIG. 14 is an enlarged, perspective view of the drive assembly;

FIG. 15 is an enlarged, perspective view of the knife assembly withparts separated;

FIG. 16 is an enlarged view of the indicated area of detail of FIG. 15;

FIG. 17 is a greatly-enlarged, perspective view of a distal end of theknife assembly;

FIG. 18 is a greatly-enlarged, perspective view of a knife drive of theknife assembly;

FIG. 19 is an enlarged, perspective view of the rotating assembly andlower jaw member with parts separated;

FIG. 20 is a cross section along line 20-20 of FIG. 19;

FIG. 21 is a greatly-enlarged, perspective view of the lower jaw member;

FIG. 22 is an enlarged, perspective view of the drive assembly;

FIG. 23 is an enlarged perspective view of the drive assembly of FIG. 22with parts separated;

FIG. 24 is a greatly-enlarged, cross section of the shaft taken alongline 24-24 of FIG. 25;

FIG. 25 is a side, cross section of the shaft and end effector assembly;

FIG. 26 is a greatly-enlarged, perspective view of a handle assembly andlatch mechanism for use with the forceps;

FIG. 27 is a greatly-enlarged view of an end effector;

FIG. 28 is a greatly-enlarged view of the drive assembly;

FIG. 29 is an enlarged, rear, perspective view of the end effector showngrasping tissue;

FIG. 30 is an enlarged view of a tissue seal;

FIG. 31 is a side, cross section of a tissue seal taken along line 31-31of FIG. 30;

FIG. 32 is an enlarged view of the end effector showing distaltranslation of the knife; and

FIG. 33 is a side, cross section of a tissue seal after separation bythe knife assembly.

DETAILED DESCRIPTION

Turning now to FIGS. 1-3, one embodiment of an endoscopic bipolarforceps 10 is shown for use with various surgical procedures andgenerally includes a housing 20, a handle assembly 30, a rotatingassembly 80, an end effector assembly 100, a knife assembly 140 (seeFIGS. 10, 12, 15-18), a drive assembly 150, a switch 500 and a latchassembly 600 which all mutually cooperate to grasp, seal and dividetubular vessels and vascular tissue 420 (FIG. 29). Although the majorityof the figure drawings depict a bipolar forceps 10 for use in connectionwith endoscopic surgical procedures, the present disclosure may be usedfor more traditional open surgical procedures. For the purposes herein,the forceps 10 is described in terms of an endoscopic instrument,however, it is contemplated that an open version of the forceps may alsoinclude the same or similar operating components and features asdescribed below.

Forceps 10 includes a shaft 12 which has a distal end 16 dimensioned tomechanically engage the end effector assembly 100 and a proximal end 14which mechanically engages the housing 20. In the drawings and in thedescriptions which follow, the term “proximal,” as is traditional, willrefer to the end of the forceps 10 which is closer to the user, whilethe term “distal” will refer to the end which is farther from the user.

Forceps 10 also includes an electrosurgical cable 310 which connects theforceps 10 to a source of electrosurgical energy, e.g., a generator (notshown). Generators such as those sold by Valleylab—a division of TycoHealthcare LP, located in Boulder, Colorado are contemplated for use asa source of electrosurgical energy, e.g., FORCE EZ™ ElectrosurgicalGenerator, FORCE FX™ Electrosurgical Generator, FORCE 1C™, FORCE 2™Generator, SurgiStat™ II. One such system is described in commonly-ownedU.S. Pat. No. 6,033,399 entitled “ELECTROSURGICAL GENERATOR WITHADAPTIVE POWER CONTROL,” the entire contents of which are herebyincorporated by reference herein. Other systems have been described incommonly-owned U.S. Pat. No. 6,187,003 entitled “BIPOLAR ELECTROSURGICALINSTRUMENT FOR SEALING VESSELS,” the entire contents of which are alsoincorporated by reference herein.

In one embodiment, the generator includes various safety and performancefeatures including isolated output, independent activation ofaccessories. In one embodiment, the electrosurgical generator includesValleylab's Instant Response™ technology features which provide anadvanced feedback system to sense changes in tissue 200 times per secondand adjust voltage and current to maintain appropriate power. TheInstant Response™ technology is believed to provide one or more of thefollowing benefits to surgical procedure:

Consistent clinical effect through all tissue types;

Reduced thermal spread and risk of collateral tissue damage;

Less need to “turn up the generator”; and

Designed for the minimally invasive environment.

Cable 310 is internally divided into cable leads (not shown) which eachtransmit electrosurgical energy through their respective feed pathsthrough the forceps 10 to the end effector assembly 100. A detaileddiscussion of the cable leads and their connections through the forceps10 is described in commonly-assigned, co-pending U.S. application Ser.No. 10/460,926 entitled “VESSEL SEALER AND DIVIDER FOR USE WITH SMALLTROCARS AND CANNULAS” by Dycus et al., which is hereby incorporated byreference in its entirety herein.

Handle assembly 30 includes a fixed handle 50, a movable handle 40, acutter lever 700 and a handle detent 710. Fixed handle 50 is integrallyassociated with housing 20 and movable handle 40 is movable relative tofixed handle 50 as explained in more detail below with respect to theoperation of the forceps 10.

In one embodiment, rotating assembly 80 is integrally associated withthe housing 20 and is rotatable approximately 180 degrees in eitherdirection about a longitudinal axis “A” (FIGS. 1 and 3). Details of therotating assembly 80 are described in more detail with respect to FIGS.9 and 10.

Housing 20 may be formed from two housing halves (not shown) which eachinclude a plurality of interfaces which are dimensioned to mechanicallyalign and engage one another to form housing 20 and enclose the internalworking components of forceps 10. A detailed discussion of the housinghalves and how they mechanically engage with one another is described incommonly-assigned, co-pending U.S. application Ser. No. 10/460,926entitled “VESSEL SEALER AND DIVIDER FOR USE WITH SMALL TROCARS ANDCANNULAS” by Dycus et al., which is hereby incorporated by reference inits entirety herein.

It is envisioned that a plurality of additional interfaces (not shown)may be disposed at various points around the periphery of housing halvesfor ultrasonic welding purposes, e.g., energy direction/deflectionpoints. It is also contemplated that housing halves (as well as theother components described below) may be assembled together in anyfashion known in the art. For example, alignment pins, snap-likeinterfaces, tongue and groove interfaces, locking tabs, adhesive ports,etc. may all be utilized either alone or in combination for assemblypurposes.

Rotating assembly 80 includes two halves 82 a and 82 b (see FIGS. 13 and19) which, when assembled, form the rotating assembly 80 which, in turn,houses the drive assembly 150 and the knife assembly 140. Half 82 bincludes a series of detents/flanges 375 a, 375 b, 375 c and 375 d whichare dimensioned to engage a pair of corresponding sockets or othermechanical interfaces (not shown) disposed within rotating half 82 a. Inone embodiment, movable handle 40 is of unitary construction and isoperatively connected to the housing 20 and the fixed handle 50 duringthe assembly process.

As mentioned above, end effector assembly 100 is attached at the distalend 14 of shaft 12 and includes a pair of opposing jaw members 110 and120. Movable handle 40 of handle assembly 30 is in mechanicalcooperation with drive assembly 150 which, together, mechanicallycooperate to impart movement of the jaw members 110 and 120 from an openposition wherein the jaw members 110 and 120 are disposed in spacedrelation relative to one another, to a clamping or closed positionwherein the jaw members 110 and 120 cooperate to grasp tissue 420 (FIG.29) therebetween.

It is envisioned that jaw members 110 and 120 of end effector assembly100 may be curved (as illustrated in FIG. 3) in order to reach specificanatomical structures and promote more consistent seals for certainprocedures. For example, it is contemplated that dimensioning the jawmembers 110 and 120 at an angle of about 45 degrees to about 70 degreesis preferred for accessing and sealing specific anatomical structuresrelevant to prostatectomies and cystectomies, e.g., the dorsal veincomplex and the lateral pedicles. Other angles may be preferred fordifferent surgical procedures. Such an end effector assembly with curvedjaw members is described in commonly-assigned, co-pending U.S.application Ser. No. 10/834,764 entitled “ELECTROSURGICAL INSTRUMENTWHICH REDUCES DAMAGE TO ADJACENT TISSUE,” by Dycus et al., which ishereby incorporated by reference in its entirety herein.

It is envisioned that the forceps 10 may be designed such that it isfully or partially disposable depending upon a particular purpose or toachieve a particular result. For example, end effector assembly 100 maybe selectively and releasably engageable with the distal end 16 of theshaft 12 and/or the proximal end 14 of shaft 12 may be selectively andreleasably engageable with the housing 20 and the handle assembly 30. Ineither of these two instances, the forceps 10 would be considered“partially disposable” or “reposable,” i.e., a new or different endeffector assembly 100 (or end effector assembly 100 and shaft 12)selectively replaces the old end effector assembly 100 as needed. As canbe appreciated, the presently disclosed electrical connections wouldhave to be altered to modify the instrument to a reposable forceps.

Turning now to the more detailed features of the present disclosure,movable handle 40 includes a finger loop 41 which has an aperture 42defined therethrough which enables a user to grasp and move the movablehandle 40 relative to the fixed handle 50. FIGS. 1 and 2 illustrate amovable handle 40 with finger loop 41 designed to be grasped and movedby a thumb, while FIG. 3 illustrates a movable handle 40 with fingerloop 41 designed to be grasped and moved by one or more fingers.Further, the movable handle 40 of FIGS. 1 and 2 is on the proximal sideof fixed handle 50, while the movable handle 40 of FIG. 3 is on thedistal side of fixed handle 50. Movable handle 40 may also include oneore more ergonomically-enhanced gripping elements (not shown) disposedalong the inner peripheral edge of aperture 42 or on fixed handle 50which is designed to facilitate gripping of the handles 40 and 50 duringactivation. It is envisioned that the gripping element may include oneor more protuberances, scallops and/or ribs to enhance gripping.

As best seen in FIGS. 1 and 2, movable handle 40 is selectively moveableabout a pivot point 29 from a first position (FIG. 1) relative to fixedhandle 50 to a second position (FIG. 2) in closer proximity to the fixedhandle 50 which, as explained below, imparts movement of the jaw members110 and 120 relative to one another. It is contemplated that there maybe intermediate positions between those shown in FIGS. 1 and 2, e.g.,discrete closure points which correspond to ratchet positions asdiscussed in more detail below. Additionally, continued movement of themoveable handle 40 towards the fixed handle 50 first engages switch 500,which causes the tissue to be sealed, and then engages knife assembly140, which cuts the tissue. Operation of the forceps is discussedfurther below.

As best seen in FIGS. 1-3 and 26, the lower end of the movable handle 40includes a flange 90. Flange 90 also includes an end 95 which rideswithin a predefined channel 52 (see FIG. 26) and mechanically engageswith ramps 57 disposed within fixed handle 50. Additional features withrespect to the end 95 are explained below in the detailed discussion ofthe operational features of the forceps 10.

Movable handle 40 is designed to provide a distinct mechanical advantageover conventional handle assemblies due to the position of the pivotpoint 29 relative to the longitudinal axis “A” of the shaft 12 and thedisposition of the drive assembly 150 along longitudinal axis “A.” Inother words, it is envisioned that by positioning the pivot point 29above the drive assembly 150, the user gains lever-like mechanicaladvantage to actuate the jaw members 110 and 120 enabling the user toclose the jaw members 110 and 120 with lesser force while stillgenerating the required forces necessary to affect a proper andeffective tissue seal and to cut the tissue 420. It is also envisionedthat the unilateral design of the end effector assembly 100 will alsoincrease mechanical advantage as explained in more detail below.

As shown best in FIGS. 4-8, the end effector assembly 100 includesopposing jaw members 110 and 120 which cooperate to effectively grasptissue 420 for sealing purposes. The end effector assembly 100 isdesigned as a unilateral assembly in this particular embodiment, i.e.,jaw member 120 is fixed relative to the shaft 12 and jaw member 110pivots about a pivot pin 103 to grasp tissue 420. A bilateral jawassembly is also envisioned wherein both jaw members are movable.

More particularly, the unilateral end effector assembly 100 includes onestationary or fixed jaw member 120 mounted in fixed relation to theshaft 12 and pivoting jaw member 110 mounted about a pivot pin 103attached to the stationary jaw member 120. A reciprocating sleeve 60 isslidingly disposed within the shaft 12 and is remotely operable by thedrive assembly 150. The pivoting jaw member 110 includes a detent orprotrusion 117 which extends from jaw member 110 through an aperture 62disposed within the reciprocating sleeve 60 (FIG. 8). The pivoting jawmember 110 is actuated by sliding the sleeve 60 axially within the shaft12 such that a distal end 63 of the aperture 62 abuts against the detent117 on the pivoting jaw member 110 (see FIGS. 7 and 8). Pulling thesleeve 60 proximally closes the jaw members 110 and 120 about tissue 420grasped therebetween and pushing the sleeve 60 distally opens the jawmembers 110 and 120 for grasping purposes.

As best illustrated in FIGS. 4 and 6, a knife channel 115 a and 115 bruns through the center of the jaw members 110 and 120, respectively,such that a knife blade 185 from the knife assembly 140 can cut thetissue 420 grasped between the jaw members 110 and 120 when the jawmembers 110 and 120 are in a closed position. More particularly, theknife blade 185 can only be advanced through the tissue 420 when the jawmembers 110 and 120 are closed thus preventing accidental or prematureactivation of the knife blade 185 through the tissue 420. Put simply,the knife channel 115 (made up of half channels 115 a and 115 b) isblocked when the jaws members 110 and 120 are opened and the knifechannel 115 is aligned for distal activation when the jaw members 110and 120 are closed (see FIGS. 25 and 27). It is also envisioned that theunilateral end effector assembly 100 may be structured such thatelectrical energy can be routed through the sleeve 60 at the protrusion117 contact point with the sleeve 60 or using a “brush” or lever (notshown) to contact the back of the moving jaw member 110 when the jawmember 110 closes. In this instance, the electrical energy would berouted through the protrusion 117 to the stationary jaw member 120.Alternatively, a cable lead 311 may be routed to energize the stationaryjaw member 120 and the other electrical potential may be conductedthrough the sleeve 60 and transferred to the pivoting jaw member 110which establishes electrical continuity upon retraction of the sleeve60. It is envisioned that this particular envisioned embodiment willprovide at least two important safety features: 1) the knife blade 185cannot extend while the jaw members 110 and 120 are opened; and 2)electrical continuity to the jaw members 110 and 120 is made only whenthe jaw members are closed. The illustrated forceps 10 only includes theknife channel 115.

As best shown in FIG. 4, jaw member 110 also includes a jaw housing 116which has an insulative substrate or insulator 114 and an electricallyconducive surface 112. In one embodiment, insulator 114 is dimensionedto securely engage the electrically conductive sealing surface 112. Thismay be accomplished by stamping, by overmolding, by overmolding astamped electrically conductive sealing plate and/or by overmolding ametal injection molded seal plate. For example and as shown in FIG. 11,the electrically conductive sealing plate 112 includes a series ofupwardly extending flanges 111 a and 111 b which are designed tomatingly engage the insulator 114. The insulator 114 includes ashoe-like interface 107 disposed at a distal end thereof which isdimensioned to engage the jaw housing 116 in a slip-fit manner. Theshoe-like interface 107 may also be overmolded about the outer peripheryof the jaw 110 during a manufacturing step. It is envisioned that cablelead 311 terminates within the shoe-like interface 107 at the pointwhere cable lead 311 electrically connects to the seal plate 112 (notshown). The movable jaw member 110 also includes a wire channel 113which is designed to guide cable lead 311 into electrical continuitywith sealing plate 112.

All of these manufacturing techniques produce jaw member 110 having anelectrically conductive surface 112 which is substantially surrounded byan insulating substrate 114. In one embodiment, the insulator 114,electrically conductive sealing surface 112 and the outer,non-conductive jaw housing 116 are dimensioned to limit and/or reducemany of the known undesirable effects related to tissue sealing, e.g.,flashover, thermal spread and stray current dissipation. Alternatively,it is also envisioned that the jaw members 110 and 120 may bemanufactured from a ceramic-like material and the electricallyconductive surface(s) 112 may be coated onto the ceramic-like jawmembers 110 and 120.

Jaw member 110 includes a pivot flange 118 (FIG. 6) which includes aprotrusion 117. Protrusion 117 extends from pivot flange 118 andincludes an arcuately-shaped inner surface 111 dimensioned to matinglyengage the aperture 62 of sleeve 60 upon retraction thereof. Pivotflange 118 also includes a pin slot 119 which is dimensioned to engagepivot pin 103 to allow jaw member 110 to rotate relative to jaw member120 upon retraction of the reciprocating sleeve 60. As explained in moredetail below, pivot pin 103 also mounts to the stationary jaw member 120through a pair of apertures 101 a and 101 b disposed within a proximalportion of the jaw member 120.

It is envisioned that the electrically conductive sealing surface 112may also include an outer peripheral edge which has a pre-defined radiusand the insulator 114 meets the electrically conductive sealing surface112 along an adjoining edge of the sealing surface 112 in a generallytangential position. In one embodiment, at the interface, theelectrically conductive surface 112 is raised relative to the insulator114. These and other envisioned embodiments are discussed in co-pending,commonly assigned Application Serial No. PCT/US01/11412 entitled“ELECTROSURGICAL INSTRUMENT WHICH REDUCES COLLATERAL DAMAGE TO ADJACENTTISSUE” by Johnson et al. and co-pending, commonly assigned ApplicationSerial No. PCT/US01/11411 entitled “ELECTROSURGICAL INSTRUMENT WHICH ISDESIGNED TO REDUCE THE INCIDENCE OF FLASHOVER” by Johnson et al., bothof which are hereby incorporated by reference in their entirety herein.

The electrosurgical seal and/or cut can be made utilizing variouselectrode assemblies on the jaw members, such that energy is applied tothe tissue through sealing plates. This and other envisionedelectrosurgical sealing and cutting techniques are discussed inco-pending, commonly assigned application Ser. No. 10/932,612 entitled“VESSEL SEALING INSTRUMENT WITH ELECTRICAL CUTTING MECHANISM” by Johnsonet al., which is hereby incorporated by reference in its entiretyherein.

In one embodiment, the electrically conductive surface 112 and theinsulator 114, when assembled, form a longitudinally-oriented slot 115 adefined therethrough for reciprocation of the knife blade 185. It isenvisioned that the knife channel 115 a cooperates with a correspondingknife channel 115 b defined in stationary jaw member 120 to facilitatelongitudinal extension of the knife blade 185 along a preferred cuttingplane to effectively and accurately separate the tissue 420 along theformed tissue seal 450 (see FIGS. 30 and 33).

Jaw member 120 includes similar elements to jaw member 110 such as jawhousing 126 having an insulator 124 and an electrically conductivesealing surface 122 which is dimensioned to securely engage theinsulator 124. Likewise, the electrically conductive surface 122 and theinsulator 124, when assembled, include a longitudinally-oriented channel115 a defined therethrough for reciprocation of the knife blade 185. Asmentioned above, when the jaw members 110 and 120 are closed abouttissue 420, knife channels 115 a and 115 b form a complete knife channel115 to allow longitudinal extension of the knife blade 185 in a distalfashion to sever tissue 420 along the tissue seal 450. It is alsoenvisioned that the knife channel 115 may be completely disposed in oneof the two jaw members, e.g., jaw member 120, depending upon aparticular purpose. It is envisioned that the fixed jaw member 120 maybe assembled in a similar manner as described above with respect to jawmember 110.

As best seen in FIG. 4, jaw member 120 includes a series of stop members750 disposed on the inner facing surfaces of the electrically conductivesealing surface 122 to facilitate gripping and manipulation of tissueand to define a gap “G” (FIG. 29) between opposing jaw members 110 and120 during sealing and cutting of tissue. It is envisioned that theseries of stop members 750 may be employed on one or both jaw members110 and 120 depending upon a particular purpose or to achieve a desiredresult. A detailed discussion of these and other envisioned stop members750 as well as various manufacturing and assembling processes forattaching and/or affixing the stop members 750 to the electricallyconductive sealing surfaces 112, 122 are described in commonly-assigned,co-pending U.S. Application Serial No. PCT/US01/11413 entitled “VESSELSEALER AND DIVIDER WITH NON-CONDUCTIVE STOP MEMBERS” by Dycus et al.which is hereby incorporated by reference in its entirety herein.

Jaw member 120 is designed to be fixed to the end of a rotating tube 160which is part of the rotating assembly 80 such that rotation of the tube160 will impart rotation to the end effector assembly 100 (see FIGS. 13and 19). Jaw member 120 includes a rear C-shaped cuff 170 having a slot177 defined therein which is dimensioned to receive a slide pin 171.More particularly, slide pin 171 includes a slide rail 176 which extendssubstantially the length thereof which is dimensioned to slide intofriction-fit engagement within slot 177. A pair of chamfered plates 172a and 172 b extend generally radially from the slide rail 176 andinclude a radius which is substantially the same radius as the outerperiphery of the rotating tube 160 such that the shaft 12 can encompasseach of the same upon assembly.

As best shown in FIGS. 19 and 20, the rotating tube 160 includes anelongated guide slot 167 disposed in an upper portion thereof which isdimensioned to carry cable lead 311 therealong. The chamfered plates 172a and 172 b also form a wire channel 175 which is dimensioned to guidethe cable lead 311 from the tube 160 and into the movable jaw member 110(see FIG. 4). Cable lead 311 carries a first electrical potential tomovable jaw 110.

As shown in FIG. 19, the distal end of the tube 160 is generallyC-shaped to include two upwardly extending flanges 162 a and 162 b whichdefine a cavity 165 for receiving the proximal end of the fixed jawmember 120 inclusive of C-shaped cuff 170 and slide pin 171 (see FIG.21). In one embodiment, the tube cavity 165 retains and secures the jawmember 120 in a friction-fit manner, however, the jaw member 120 may bewelded to the tube 160 depending upon a particular purpose. Tube 160also includes an inner cavity 169 defined therethrough whichreciprocates the knife assembly 140 upon distal activation thereof andan elongated guide rail 163 which guides the knife assembly 140 duringdistal activation (see FIG. 20). The details with respect to the knifeassembly are explained in more detail with respect to FIGS. 15-18. Theproximal end of tube 160 includes a laterally oriented slot 168 which isdesigned to interface with the rotating assembly 80 as described below.

FIG. 19 also shows the rotating assembly 80 which includes C-shapedrotating halves 82 a and 82 b which, when assembled about tube 160, forma generally circular rotating member 82. More particularly, eachrotating half, e.g., 82 b, includes a series of mechanical interfaces375 a, 375 b, 375 c and 375 d which matingly engage a correspondingseries of mechanical interfaces in the other half, e.g., 82 a, to formrotating member 82. Half 82 b also includes a tab 89 b which, togetherwith a corresponding tab 89 a disposed on half 82 a (phantomlyillustrated), cooperate to matingly engage slot 168 disposed on tube160. As can be appreciated, this permits selective rotation of the tube160 about axis “A” by manipulating the rotating member 82 in thedirection of the arrow “B” (see FIG. 2).

As best shown in the exploded view of FIG. 11, jaw members 110 and 120are pivotably mounted with respect to one another such that jaw member110 pivots in a unilateral fashion from a first open position to asecond closed position for grasping and manipulating tissue 420. Moreparticularly, fixed jaw member 120 includes a pair of proximal, upwardlyextending flanges 125 a and 125 b which define a cavity 121 dimensionedto receive flange 118 of movable jaw member 110 therein. As explained indetail below with respect to the operation of the jaw members 110 and120, proximal movement of the tube 60 engages detent 117 to pivot thejaw member 110 to a closed position.

FIGS. 1-3 show the housing 20 and the component features thereof,namely, the handle assembly 30, the rotating assembly 80, the knifeassembly 140, the drive assembly 150, the switch 500, the latch assembly600 and a cutter lever 700.

The housing includes two halves (constructed similarly to the halves ofrotating assembly 80, as discussed above with reference to FIG. 19)which, when mated, form housing 20. As can be appreciated, housing 20,once formed, houses the various assemblies identified above which willenable a user to selectively manipulate, grasp, seal and sever tissue420 in a single action. In one embodiment, each half of the housingincludes a series of mechanical interfacing components (not shown) whichalign and/or mate with a corresponding series of mechanical interfacesto align the two housing halves about the inner components andassemblies. The housing halves can then be sonic welded to secure thehousing halves once assembled.

The movable handle 40 includes clevis 45 which pivots about pivot point29 to pull the reciprocating sleeve 60 along longitudinal axis “A” andforce a drive flange 47 against the drive assembly 150 which, in turn,closes the jaw members 110 and 120, as explained above. As mentionedabove, the lower end of the movable handle 40 includes a flange 90 whichhas an end 95 which rides within a predefined channel 52 disposed withinfixed handle 50 (see FIG. 26). The arrangement of the clevis 45 and thepivot point 29 of the movable handle 40 provides a distinct mechanicaladvantage over conventional handle assemblies due to the position of thepivot point 29 relative to the longitudinal axis “A” of the drive flange47. In other words, by positioning the pivot point 29 above the driveflange 47, the user gains lever-like mechanical advantage to actuate thejaw members 110 and 120. This reduces the overall amount of mechanicalforce necessary to close the jaw members 110 and 120 to affect a tissueseal.

Movable handle 40 also includes a finger loop 41 which defines opening42 which is dimensioned to facilitate grasping the movable handle 40. Inone embodiment, finger loop 41 includes rubber insert which enhances theoverall ergonomic “feel” of the movable handle 40.

Handle assembly 30 further includes a cutter lever 700 positioned withinhousing 20. When movable handle 40 is actuated (squeezed) past a certainthreshold, a switch lever 502 is depressed by movable handle 40 toinitiate a tissue seal cycle. A flexible detent 602 provides tactilefeedback that the movable handle 40 is nearing an exit of the latchsealing zone and an end of the ramps 57. When the movable handle 40 ispushed past the flexible detent 602, end 95 of flange 90 drops down fromramps 57 and the user is able to return the movable handle 40 proximallyto open the jaw members 110, 120 without cutting the seal. The user mayalso close the movable handle 40 to cut the sealed tissue 420 viaactuation of the lever 700. When closing movable handle 40 farther tocut tissue, end 95 contacts a latch spring 704, which providesresistance on the movable handle 40. This provides an indication to theuser that tissue cutting is about to begin.

The movable handle 40 or a handle detent 710 contacts the cutter lever700, which activates knife assembly 140, which severs the tissue 420. Ascan be appreciated, this prevents accidental or premature severing oftissue 420 prior to completion of the tissue seal 450. The generator mayprovide an audible signal or other type of feedback when the seal cycleis complete. The surgeon can then safely cut the seal or return themovable handle 40 without cutting. In an alternative method, anelectromechanical, mechanical or electrical feature could preventcutting without initially sealing or without the surgeon activating aspecial over-ride feature.

Fixed handle 50 includes a channel 52 (FIG. 26) defined therein which isdimensioned to receive end 95 of flange 90 when movable handle 40 isactuated. The end 95 of flange 90 is dimensioned for facile receptionwith ramps 57 within channel 52 of fixed handle 50. It is envisionedthat flange 90 may be dimensioned to allow a user to selectively,progressively and/or incrementally move jaw members 110 and 120 relativeto one another from the open to closed positions. For example, it iscontemplated that end 95 and ramps 57 may include a ratchet-likeinterface (FIGS. 1-3) which lockingly engages the movable handle 40 and,therefore, jaw members 110 and 120 at selective, incremental positionsrelative to one another depending upon a particular purpose. Such aratchet-like interface can also prevent the movable handle 40 frombecoming unactuated prior to the severing of tissue 420.

It is also contemplated that the ratchet-like interface between the end95 and ramps 57 are configured such that a catch basin is disposedbetween each step of the ratchet. A catch basin is described incommonly-assigned, co-pending U.S. application Ser. No. 10/460,926entitled “VESSEL SEALER AND DIVIDER FOR USE WITH SMALL TROCARS ANDCANNULAS” by Dycus et al., which is hereby incorporated by reference inits entirety herein, and can be utilized to be a stopping point betweeneach of the functions that the movable handle 40 can control (i.e.,manipulation, clamping, sealing and cutting). Employing such a catchbasin will enable the user to selectively advance the movable handle 40,while ensuring the functions are carried out in the proper order.

Other mechanisms may also be employed to control and/or limit themovement of movable handle 40 relative to fixed handle 50 (and jawmembers 110 and 120) such as, e.g., hydraulic, semi-hydraulic, linearactuator(s), gas-assisted mechanisms and/or gearing systems.

In one embodiment, forceps 10 includes at least one tactile elementwhich provides tactile feedback to the user to signify when tissue isbeing grasped, when the tissue has been sealed and/or when the tissuehas been cut. Such a tactile element may include the turning on/off oflights (not shown) on housing 20 or mechanical vibrations being createdin the fixed handle 50 or movable handle 40. It is further envisionedfor a sensor to be disposed on or within forceps 10 to alert to the userwhen one or more completion stages has occurred, i.e., at the completionof tissue grasping, tissue sealing and/or tissue cutting.

As best illustrated in FIG. 26, housing halves form an internal cavitywhich predefines the channel 52 within fixed handle 50 such that anentrance pathway 51 and an exit pathway 58 are formed for reciprocationof the end 95 of flange 90 therein. When assembled, two ramps 57 arepositioned to define a rail or track 192, such that the flange 90 canfit between the ramps 57 and end 95 moves along the track 192. Duringmovement of end 95 of flange 90 along the entrance and exit pathways 51and 58, respectively, the end 95 rides along track 192 according to theparticular dimensions of the ramps 57, which, as can be appreciated,predetermines part of the overall pivoting motion of movable handle 40relative to fixed handle 50.

As best illustrated in FIGS. 1 and 2, once actuated, movable handle 40moves in a generally arcuate fashion towards fixed handle 50 about pivotpoint 29. End 95 of flange 90 moves along ramps 57 (shown as a singleramp in FIGS. 1-3 for clarity) which forces drive flange 47 against thedrive assembly 150 which, in turn, pulls reciprocating sleeve 60 in agenerally proximal direction to close jaw member 110 relative to jawmember 120. Continued actuation of movable handle 40 forces end 95 offlange 90 farther along ramps 57 and forces the movable handle 40 orcutter lever 700 into a contact 502 of switch 500, which causes thesealing of tissue 420 to occur. Continued actuation of movable handle 40then forces movable handle detent 710 into cutter lever 700 to initiateengagement thereof. A detailed discussion of how the sealing occurs,including by electro-mechanical means, is described incommonly-assigned, co-pending U.S. application Ser. No. 10/932,612entitled “VESSEL SEALING INSTRUMENT WITH ELECTRICAL CUTTING MECHANISM”by Johnson et al., which is hereby incorporated herein.

Continued actuation of movable handle 40 forces end 95 of flange 90farther along the ramps 57 and into a flexible latch detent 602. Theuser feels a resistance when the end 95 contacts the flexible latchdetent 602, which signifies that the device is about to exit the sealingposition and either cut or return to its original position withoutcutting. To cut the tissue seal 450, the user continues to actuate themovable handle 40, such that the cutter lever 700 activates knifeassembly 140, which in turn severs the tissue seal 450. At this cuttingstage, the end 95 contacts a detent rib 704 which provides increasedresistance to the user indicating that cutting of the tissue is about tobegin. The end 95 slides distally along detent rib 704 (in theembodiment shown in FIG. 3, the detent rib 704 is contacted proximally).When the cut is complete, the detent rib 704 may stop the motion of theend 95 and allow flange 90 to follow its return path 58 (FIG. 26), asdiscussed above. Therefore, a full actuation of movable handle 40 graspsand clamps tissue 420, seals the tissue 420, and cuts the tissue seal450, before returning the movable handle 40 to its original, unactuatedposition.

FIG. 3 illustrates the forceps 10 with the movable handle 40 located onthe distal side of fixed handle 50. As can be appreciated, the internaldynamics of this embodiment are similar to those of the forcepsillustrated in FIGS. 1 and 2, thus causing the forceps 10 to function ina comparable way.

It is envisioned that the flexible latch detent 602 may include one ormore electro-mechanical switches, similar to those of switch 500, toseal the tissue 420. In this embodiment, handswitch 500 and contact 502are not necessary. Details relating to the handswitch are discussedbelow.

It is also envisioned that latch spring 704 may include one or moremechanical or electro-mechanical switches or activations to drive theknife assembly 140 to cut the tissue seal 450, such that when end 95contacts the latch spring 704, the tissue seal 450 is automaticallysevered.

The operating features and relative movements of the internal workingcomponents of the forceps 10 are shown as phantom lines in the variousfigures.

As the movable handle 40 is actuated and flange 90 is incorporated intochannel 52 of fixed handle 50, the drive flange 47, through themechanical advantage of the above-the-center pivot points, biases a ringflange 154 of drive ring 159 which, in turn, compresses a drive spring67 against a rear ring 156 of the drive assembly 150 (FIG. 28). As aresult thereof, the rear ring 156 reciprocates sleeve 60 proximallywhich, in turn, closes jaw member 110 onto jaw member 120. It isenvisioned that the utilization of an over-the-center pivoting mechanismwill enable the user to selectively compress the drive spring 67 aspecific distance which, in turn, imparts a specific pulling load on thereciprocating sleeve 60 which is converted to a rotational torque aboutthe jaw pivot pin 103. As a result, a specific closure force can betransmitted to the opposing jaw members 110 and 120.

FIG. 26 shows the initial actuation of movable handle 40 towards fixedhandle 50 which causes the end 95 of flange 90 to move generallyproximally and upwardly along entrance pathway 51 (this illustration isthe embodiment of the forceps shown in FIG. 3; the internal environmentof the forceps of FIGS. 1 and 2 is similarly situated). During movementof the flange 90 along the entrance and exit pathways 51 and 58,respectively, the end 95 rides along track 192 along the ramps 57. Oncethe tissue 420 is clamped, sealed and cut, end 95 clears edge 193 andmovable handle 40 and flange 90 are redirected to exit pathway 58, wherethe movable handle 40 returns to its unactuated position.

As mentioned above, the jaw members 110 and 120 may be opened, closedand rotated to manipulate tissue 420 until sealing is desired. Thisenables the user to position and re-position the forceps 10 prior toactivation and sealing. The end effector assembly 100 is rotatable aboutlongitudinal axis “A” through rotation of the rotating assembly 80. Itis envisioned that the feed path of the cable lead 311 through therotating assembly 80, along shaft 12 and, ultimately, to the jaw member110 enables the user to rotate the end effector assembly 100approximately 180 degrees in both the clockwise and counterclockwisedirections without tangling or causing undue strain on cable lead 311.As can be appreciated, this facilitates the grasping and manipulation oftissue 420.

Again as best shown in FIGS. 1 and 2, cutter lever 700 mounts adjacentmovable handle 40 and cooperates with the knife assembly 140 toselectively translate knife blade 185 through a tissue seal 450.

Distal activation of the movable handle 40 (in the embodiment shown inFIGS. 1 and 2) forces the cutter lever 700 distally, which, as explainedin more detail below, ultimately extends the knife blade 185 through thetissue 420. A knife spring 350 biases the knife assembly 70 in aretracted position such that after severing tissue 420 the knife blade185 and the knife assembly 70 are automatically returned to a pre-firingposition.

Drive assembly 150 includes reciprocating sleeve 60, drive housing 158,drive spring 67, drive ring 159, drive stop 155 and guide sleeve 157which all cooperate to form the drive assembly 150. More particularlyand as best shown in FIGS. 22 and 23, the reciprocating sleeve 60includes a distal end 65 which as mentioned above has an aperture 62formed therein for actuating the detent 117 of jaw member 110. In oneembodiment, the distal end 65 includes a scoop-like support member 69for supporting a proximal end 61 of the fixed jaw member 120 therein.The proximal end 61 of the reciprocating sleeve 60 includes a slot 68defined therein which is dimensioned to slidingly support the knifeassembly 70 for longitudinal reciprocation thereof to sever tissue 420.The slot 68 also permits retraction of the reciprocating sleeve 60 overthe knife assembly 140 during the closing of jaw member 110 relative tojaw member 120.

The proximal end 61 of the reciprocating sleeve 60 is positioned withinan aperture 151 in drive housing 158 to permit selective reciprocationthereof upon actuation of the movable handle 40. The drive spring 67 isassembled atop the drive housing 158 between a rear stop 156 of thedrive housing 158 and a forward stop 154 of the drive ring 159 such thatmovement of the forward stop 154 compresses the drive spring 67 againstthe rear stop 156 which, in turn, reciprocates the drive sleeve 60. As aresult thereof, the jaw members 110 and 120 and the movable handle 40are biased by drive spring 67 in an open configuration. The drive stop155 is fixedly positioned atop the drive housing 158 and biases themovable handle 40 when actuated such that the drive flange 47 forces thestop 154 of the drive ring 159 proximally against the force of the drivespring 67. The drive spring 67, in turn, forces the rear stop 156proximally to reciprocate the sleeve 60. In one embodiment, the rotatingassembly 80 is located proximal to the drive flange 47 to facilitaterotation of the end effector assembly 100. The guide sleeve 157 mateswith the proximal end 61 of the reciprocating sleeve 60 and affixes tothe drive housing 158. The assembled drive assembly 150 is shown best inFIG. 14.

As best shown in FIGS. 12 and 15-18, the knife assembly 140 includes anelongated rod 182 having a bifurcated distal end comprising prongs 182 aand 182 b which cooperate to receive a knife bar 184 therein. The knifeassembly 180 also includes a proximal end 183 which is keyed tofacilitate insertion into tube 160 of the rotating assembly 80. A knifewheel 148 is secured to the knife bar 182 by a pin 143. Moreparticularly, the elongated knife rod 182 includes apertures 181 a and181 b which are dimensioned to receive and secure the knife wheel 148 tothe knife rod 182 such that longitudinal reciprocation of the knifewheel 148, in turn, moves the elongated knife rod 182 to sever tissue420.

In one embodiment, the knife wheel 148 is donut-like and includes rings141 a and 141 b which define a drive slot 147 designed to receive adrive bar (not shown) such that actuation of the movable handle 40forces the drive bar and the knife wheel 148 distally. It is envisionedthat apertures 181 a and 181 b may be used for different configurations.As such, pin 143 is designed for attachment through either aperture 181a or 181 b to mount the knife wheel 148 (see FIG. 18). Knife wheel 148also includes a series of radial flanges 142 a and 142 b which aredimensioned to slide along both channel 163 of tube 160 and slot 68 ofthe reciprocating sleeve 60 (see FIG. 9).

As mentioned above, the knife rod 182 is dimensioned to mount the knifebar 184 between prongs 182 a and 182 b, which can be in a friction-fitengagement. The knife bar 184 includes a series of steps 186 a, 186 band 186 c which reduce the profile of the knife bar 184 towards thedistal end thereof. The distal end of the knife bar 184 includes a knifesupport 188 which is dimensioned to retain knife blade 185. The end ofthe knife support 188 can include a chamfered edge 188 a. It isenvisioned that the knife blade 185 may be welded to the knife support188 or secured in any manner known in the trade.

As best shown in FIGS. 1 and 2, as the tissue is securely grasped andthe cutter lever 700 advances distally due to actuation of movablehandle 40, switch 500 activates, by virtue of movable handle 40 engagingcontact 502. At this point, electrosurgical energy is transferredthrough cable leads to jaw members 110 and 120, as described incommonly-assigned, co-pending U.S. application Ser. No. 10/460,926entitled “VESSEL SEALER AND DIVIDER FOR USE WITH SMALL TROCARS ANDCANNULAS” by Dycus et al., which is hereby incorporated by reference inits entirety herein. As can be appreciated from the mechanics of theforceps 10, the switch 500 cannot fire unless the jaw members 110 and120 are closed. A sensor (not shown) may be included in the generator orthe housing which prevents activation unless the jaw members 110 and 120have tissue 420 held therebetween. In addition, other sensor mechanismsmay be employed which determine pre-surgical, concurrent surgical (i.e.,during surgery) and/or post surgical conditions. The sensor mechanismsmay also be utilized with a closed-loop feedback system coupled to theelectrosurgical generator to regulate the electrosurgical energy basedupon one or more pre-surgical, concurrent surgical or post surgicalconditions. Various sensor mechanisms and feedback systems are describedin commonly-owned, co-pending U.S. patent application Ser. No.10/427,832 entitled “METHOD AND SYSTEM FOR CONTROLLING OUTPUT OF RFMEDICAL GENERATOR” filed on May 1, 2003 the entire contents of which arehereby incorporated by reference herein.

In one embodiment, the jaw members 110 and 120 are electrically isolatedfrom one another such that electrosurgical energy can be effectivelytransferred through the tissue 420 to form seal 450. For example and asbest illustrated in FIGS. 24 and 25, each jaw member, e.g., 110,includes a uniquely-designed electrosurgical cable path disposedtherethrough which transmits electrosurgical energy to the electricallyconductive sealing surface 112. It is envisioned that jaw member 110 mayinclude one or more cable guides or crimp-like electrical connectors todirect cable lead 311 towards electrically conductive sealing surface112. In one embodiment, cable lead 311 is held loosely but securelyalong the cable path to permit rotation of the jaw member 110 aboutpivot 103. As can be appreciated, this isolates electrically conductivesealing surface 112 from the remaining operative components of the endeffector assembly 100, jaw member 120 and shaft 12. The secondelectrical potential is conducted to jaw member 120 through tube 160.The two potentials are isolated from one another by virtue of theinsulative sheathing surrounding cable lead 311.

It is contemplated that utilizing a cable feed path for cable lead 311and by utilizing a conductive tube 160 to carry the first and secondelectrical potentials not only electrically isolates each jaw member 110and 120 but also allows the jaw members 110 and 120 to pivot about pivotpin 103 without unduly straining or possibly tangling cable lead 311.Moreover, it is envisioned that the simplicity of the electricalconnections greatly facilitates the manufacturing and assembly processand assures a consistent and tight electrical connection for thetransfer of energy through the tissue 420.

As discussed in commonly-assigned, co-pending U.S. application Ser. No.10/460,926 entitled “VESSEL SEALER AND DIVIDER FOR USE WITH SMALLTROCARS AND CANNULAS” by Dycus et al., which is hereby incorporated byreference in its entirety herein, it is envisioned that select cableleads are fed through halves 82 a and 82 b of the rotating assembly 80in such a manner to allow rotation of the shaft 12 (via rotation of therotating assembly 80) in the clockwise or counter-clockwise directionwithout unduly tangling or twisting the cable leads. More particularly,select cable leads are fed through a series of conjoining slots 84 a, 84b, 84 c and 84 d located in the two halves 82 a and 82 b of the rotatingassembly 80. In one embodiment, each conjoining pair of slots, e.g., 84a, 84 b and 84 c, 84 d, is large enough to permit rotation of therotating assembly 80 without unduly straining or tangling the cableleads. The presently disclosed cable lead feed path is envisioned toallow rotation of the rotation assembly approximately 180 degrees ineither direction.

Turning back to FIGS. 1-3 which show a view of the housing 20, rotatingassembly 80, movable handle 40, fixed handle 50, latch assembly 600,switch 500 and cutter lever 700, it is envisioned that all of thesevarious component parts along with the shaft 12 and the end effectorassembly 100 are assembled during the manufacturing process to form apartially and/or fully disposable forceps 10. For example and asmentioned above, the shaft 12 and/or end effector assembly 100 may bedisposable and, therefore, selectively/releasably engagable with thehousing 20 and rotating assembly 80 to form a partially disposableforceps 10 and/or the entire forceps 10 may be disposable after use.

Once assembled, drive spring 67 is poised for compression atop drivehousing 158 upon actuation of the movable handle 40. More particularly,movement of the movable handle 40 about pivot point 29 reciprocates theflange 90 into fixed handle 50 and forces drive flange 47 against flange154 of drive ring 159 to compress drive spring 67 against the rear stop156 to reciprocate the sleeve 60 (see FIG. 28).

The switch 500 is prevented from firing before the tissue 420 is clampedby jaw members 110 and 120. For the sealing to take place, the movablehandle 40 should be actuated far enough to contact (or, alternatively,for the cutter lever 700 to contact) the switch 500, contact 502 or asensor (not shown). Before the switch 500 is contacted, the movablehandle 40 should travel sufficiently far enough to cause jaw members 110and 120 to be clamped. It is envisioned that the opposing jaw members110 and 120 may be rotated and partially opened and closed beforeactivation of switch 500 which, as can be appreciated, allows the userto grip and manipulate the tissue 420 before the tissue 420 is sealed.

It is envisioned that configuring the pivot 29 above or relative to alongitudinal axis defined through the shaft provides an increasedmechanical advantage, thus facilitating and easing selective compressionof the drive spring 67 a specific distance which, in turn, imparts aspecific load on the reciprocating sleeve 60. As best seen in FIG. 2,the moveable handle 40 includes a drive cam surface 49′ which isdesigned in-line with the longitudinal axis “A,” which together with theposition of the pivot 28 being disposed above axis “A,” increase themechanical advantage of the movable handle 40 and reduce the amount offorce necessary to actuate the jaw members 110, 120 with the preferredclosure force. The load of the reciprocating sleeve 60 is converted to atorque about the jaw pivot 103. As a result, a specific closure forcecan be transmitted to the opposing jaw members 110 and 120 between therange of about 3 kg/cm² to about 16 kg/cm². As mentioned above, the jawmembers 110 and 120 may be opened, closed and rotated to manipulatetissue 420 until sealing is desired. This enables the user to positionand re-position the forceps 10 prior to activation and sealing.

Once the desired position for the sealing site is determined and the jawmembers 110 and 120 are properly positioned, movable handle 40 may beactuated farther such that the switch 500 is engaged to seal the tissue420 with electrosurgical energy. Continued actuation of movable handle40 engages knife assembly 140 (as discussed above), which causes thetissue seal 450 to be severed.

It is envisioned that the end effector assembly 100 and/or the jawmembers 110 and 120 may be dimensioned to off-load some of the excessiveclamping forces to prevent mechanical failure of certain internaloperating elements of the end effector 100.

As can be appreciated, the combination of the increased mechanicaladvantage provided by the above-the-axis pivot 29 along with thecompressive force associated with the drive spring 67 facilitate andassure consistent, uniform and accurate closure pressure about thetissue 420 within the desired working pressure range of about 3 kg/cm²to about 16 kg/cm² and, preferably, about 7 kg/cm² to about 13 kg/cm².By controlling the intensity, frequency and duration of theelectrosurgical energy applied to the tissue 420, the user caneffectively seal tissue.

In one embodiment, the electrically conductive sealing surfaces 112 and122 of the jaw members 110 and 120, respectively, are relatively flat toavoid current concentrations at sharp edges and to avoid arcing betweenhigh points. In addition and due to the reaction force of the tissue 420when engaged, jaw members 110 and 120 can be manufactured to resistbending. For example, the jaw members 110 and 120 may be tapered alongthe width thereof which is advantageous for two reasons: 1) the taperwill apply constant pressure for a constant tissue thickness atparallel; 2) the thicker proximal portion of the jaw members 110 and 120will resist bending due to the reaction force of the tissue 420.

As mentioned above, at least one jaw member, e.g., 120, may include astop member 750 which limits the movement of the two opposing jawmembers 110 and 120 relative to one another. In one embodiment, the stopmember 750 extends a predetermined distance from the sealing surface 122(according to the specific material properties [e.g., compressivestrength, thermal expansion, etc.]) to yield a consistent and accurategap distance “G” during sealing (FIG. 29). The gap distance betweenopposing sealing surfaces 112 and 122 during sealing ranges from about0.001 inches to about 0.006 inches and, desirably, between about 0.002and about 0.003 inches. It is envisioned that the non-conductive stopmembers 750 may be molded onto the jaw members 110 and 120 (e.g.,overmolding, injection molding, etc.), stamped onto the jaw members 110and 120 or deposited (e.g., deposition) onto the jaw members 110 and120. For example, one technique involves thermally spraying a ceramicmaterial onto the surface of the jaw member 110 and 120 to form the stopmembers 750. Several thermal spraying techniques are contemplated whichinvolve depositing a broad range of heat resistant and insulativematerials on various surfaces to create stop members 750 for controllingthe gap distance between electrically conductive surfaces 112 and 122.

As energy is being selectively transferred to the end effector assembly100, across the jaw members 110 and 120 and through the tissue 420, atissue seal 450 forms isolating two tissue halves 420 a and 420 b. Withother known vessel sealing instruments, the user then removes andreplaces the forceps 10 with a cutting instrument (not shown) ormanually activates another switch to divide the tissue halves 420 a and420 b along the tissue seal 450. As can be appreciated, this is bothtime consuming and tedious and may result in inaccurate tissue divisionacross the tissue seal 450 due to misalignment or misplacement of thecutting instrument along the ideal tissue cutting plane.

As explained in detail above, the present disclosure incorporates aknife assembly 140 which, when activated via the handle assembly 30,progressively and selectively divides the tissue 420 along an idealtissue plane in precise manner to effectively and reliably divide thetissue 420 into two sealed halves 420 a and 420 b with a tissue gap 475therebetween (see FIG. 33). The knife assembly 140 in conjunction withthe handle assembly 30 allows the user to quickly separate the tissue420 immediately after sealing without substituting a cutting instrumentthrough a cannula or trocar port and without having to perform adifferent action (e.g., manually activating a switch or pulling atrigger). As can be appreciated, accurate sealing and dividing of tissue420 is accomplished with a single, continuous motion using the sameforceps 10.

It is envisioned that knife blade 185 may also be coupled to the same oran alternative electrosurgical energy source to facilitate separation ofthe tissue 420 along the tissue seal 450 (not shown). Moreover, it isenvisioned that the angle of the tip of the knife blade 185 may bedimensioned to provide more or less aggressive cutting angles dependingupon a particular purpose. For example, the knife blade 185 may bepositioned at an angle which reduces “tissue wisps” associated withcutting. Moreover, the knife blade 185 may be designed having differentblade geometries such as serrated, notched, perforated, hollow, concave,convex etc. depending upon a particular purpose or to achieve aparticular result.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. For example, it may be preferable to add other features tothe forceps 10, e.g., an articulating assembly to axially displace theend effector assembly 100 relative to the elongated shaft 12.

It is also contemplated that the forceps 10 (and/or the electrosurgicalgenerator used in connection with the forceps 10) may include a sensoror feedback mechanism (not shown) which automatically selects theappropriate amount of electrosurgical energy to effectively seal theparticularly-sized tissue grasped between the jaw members 110 and 120.The sensor or feedback mechanism may also measure the impedance acrossthe tissue during sealing and provide an indicator (visual and/oraudible) that an effective seal has been created between the jaw members110 and 120. Examples of such sensor systems are described incommonly-owned U.S. patent application Ser. No. 10/427,832 entitled“METHOD AND SYSTEM FOR CONTROLLING OUTPUT OF RF MEDICAL GENERATOR,”filed on May 1, 2003 the entire contents of which are herebyincorporated by reference herein.

Although the figures depict the forceps 10 manipulating an isolatedvessel 420, it is contemplated that the forceps 10 may be used withnon-isolated vessels as well. Other cutting mechanisms are alsocontemplated to cut tissue 420 along the ideal tissue plane.

It is envisioned that the outer surface of the end effector assembly 100may include a nickel-based material, coating, stamping, metal injectionmolding which is designed to reduce adhesion between the jaw members 110and 120 with the surrounding tissue during activation and sealing.Moreover, it is also contemplated that the conductive surfaces 112 and122 of the jaw members 110 and 120 may be manufactured from one (or acombination of one or more) of the following materials: nickel-chrome,chromium nitride, MedCoat 2000 manufactured by The ElectrolizingCorporation of OHIO, inconel 600 and tin-nickel. The tissue conductivesurfaces 112 and 122 may also be coated with one or more of the abovematerials to achieve the same result, i.e., a “non-stick surface.” Ascan be appreciated, reducing the amount that the tissue “sticks” duringsealing improves the overall efficacy of the instrument.

One particular class of materials disclosed herein has demonstratedsuperior non-stick properties and, in some instances, superior sealquality. For example, nitride coatings which include, but not are notlimited to: TiN, ZrN, TiAlN, and CrN are preferred materials used fornon-stick purposes. CrN has been found to be particularly useful fornon-stick purposes due to its overall surface properties and optimalperformance. Other classes of materials have also been found to reducingoverall sticking. For example, high nickel/chrome alloys with a Ni/Crratio of approximately 5:1 have been found to significantly reducesticking in bipolar instrumentation. One particularly useful non-stickmaterial in this class is Inconel 600. Bipolar instrumentation havingsealing surfaces 112 and 122 made from or coated with Ni200, Ni201(˜100% Ni) also showed improved non-stick performance over typicalbipolar stainless steel electrodes.

While several embodiments of the disclosure have been shown in thefigures, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of preferred embodiments. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

What is claimed is:
 1. A method for using a bipolar forceps, the methodcomprising: providing a bipolar forceps having a housing, a shaftextending from the housing having an end effector assembly disposed atdistal end thereof including first and second jaw members, a switchconfigured to provide electrosurgical energy to the jaw members, a knifeoperably disposed between the jaw members, and a movable handleconnected to the housing; and continually moving the movable handle toboth pivot the first jaw member toward the second jaw member such thatthe first and second jaw members grasp tissue therebetween and advanceat least a portion of the knife to cut tissue grasped between the jawmembers, wherein the switch is activated prior to advancement of theknife to cut tissue and advancement of the at least a portion of theknife to cut tissue grasped between the jaw members is subsequent to thefirst jaw member being pivoted toward the second jaw member.
 2. A methodfor using a bipolar forceps according to claim 1 further comprisingrotating the shaft relative to the housing about a longitudinal axisdefined by the shaft.
 3. A method for using a bipolar forceps accordingto claim 1 further comprising grasping tissue between jaw members undera closure pressure from about 3 kg/cm² to about 16 kg/cm².
 4. A methodfor using a bipolar forceps, the method comprising: providing a bipolarforceps having a housing, a shaft extending from the housing, an endeffector assembly disposed adjacent a distal end thereof, a driveassembly disposed within the housing, a knife, and a movable handleconnected to the housing, the end effector assembly including a firstjaw member and a second jaw member; and continually moving the movablehandle to both engage the drive assembly to pivot the first jaw membertoward the second jaw member such that the first and second jaw membersgrasp tissue therebetween and advance at least a portion of the knife tocut tissue grasped between the jaw members, wherein advancement of theat least a portion of the knife to cut tissue grasped between the jawmembers is subsequent to the first jaw member being pivoted toward thesecond jaw member.
 5. A method for using a bipolar forceps, the methodcomprising: continually moving a handle of the bipolar forceps to both:pivot a first jaw member toward a second jaw member about a pivot pointto grasp tissue therebetween; and advance a knife to cut tissue graspedbetween the jaw members, wherein a switch operably associated with ahousing of the bipolar forceps is actuatable to conduct energy throughtissue grasped between the jaw members prior to advancement of the knifeto cut tissue and the knife is advanceable through the jaw members tocut tissue subsequent to movement of the first jaw member toward thesecond jaw member.
 6. A method for using a bipolar forceps according toclaim 5 further comprising rotating the shaft relative to the housingabout a longitudinal axis defined by the shaft.
 7. A method for using abipolar forceps according to claim 5 further comprising grasping tissuebetween jaw members under a closure pressure from about 3 kg/cm² toabout 16 kg/cm².
 8. A method for using a bipolar forceps, the methodcomprising: providing a bipolar forceps having a housing, a shaftextending from the housing having an end effector assembly disposed atdistal end thereof including a first jaw member pivotable relative to asecond jaw member, a switch operably associated with the housing andconfigured to provide electrosurgical energy to the jaw members, a knifeoperably disposed between the jaw members, and a movable handleconnected to the housing; activating the switch to energize the jawmembers; and after activation of the switch, continually moving themovable handle to grasp tissue between the jaw members and advance theknife to cut tissue grasped between the jaw members, wherein advancementof the knife to cut tissue grasped between the jaw members is subsequentto grasping tissue between the jaw members.